Blowing lance for carrying out top-blowing processes



Dec. 13, 1966 K. HEYER 3,291,471

BLOWING LANCE FOR CARRYING OUT TOPBLOWING PROCESSES Filed Dec. 9, .1963

INVENTOR. KLAus HEYER JM ATToRN E Y5.

United States Patent 3,291,471 BLOWING LANCE FOR CARRYING OUT TOP-BLOWING PROCESSES Klaus Heyer, Linz, Austria, assignor to Vereinigte Osterreichische Eisenund Stahlwerke Aktiengesellschaft,

Linz, Austria, a company of Austria Filed Dec. 9, 1963, Ser. No. 329,117 Claims priority, application Austria, Dec. 14, 1962, A 9,799/ 62 5 Claims. (Cl. 266-34) This invention relates to a blowing lance for the pneumatic refining of crude iron, wherein a suspension of finegrained basic admixtures, such as lime, in a gaseous oxygen-containing blowing medium is blown onto the molten charge.

Refining processes of the mentioned kind, which are often designated by the short name LD-AG processes, have been developed for refining high-phosphorus crude irons. They enable the rapid formation of a reactive slag and the preferential dephosphorization before the decarbonization.

Blowing lances have already been proposed which consist of two concentric tubes, the outer tube carrying the oxygen-containing blowing medium and the inner tube carrying a suspension of the finely divided solid substances in the blowing medium, so that the mixing of the two media is effected upon their expansion beyond the nozzle mouth. Since the supply conduits for the suspension are subjected to a very heavy wear, special measures have had to be taken for the introduction of the suspension into the inner tube. It has been proposed, for instance, to connect the inner tube directly with the lime supply container and to make the outer tube, which terminates in a nozzle, telescopically displaceable and glidable relative to the inner tube. It has also been proposed to feed the suspension into the inner tube through an elbow tube.

It has shown that the known constructions involve certain disadvantages. In the case of a telescope lance, the

inner tube has to be worked precisely and carefully all over its length; during operation, the part of the inner tube which projects from the blowing lance is exposed and can easily be damaged. Dust which collects on this part of the tube causes a heavy wear of the packings. The replacement of the packings is a complicated operation, because the whole inner tube has to be pulled out of the lance.

Also the use of elbow tubes has not proved satisfactory. In order to keep the wear at a low degree, the radius of curvature of the elbow tube has to be large. This entails the undesirable result that the distance between the lance joined to the elbow tube and the operating platform is very large. Thus, the operation of the lance is rendered more diflicult. Replacement of the elbow tube is timeconsuming and requires additional installations because of the heavy weight thereof.

It is an object of the invention to avoid these disadvantages and diflficulties. In particular, the invention has in view that the inner tube which feeds the suspension is perfectly sealed against the outside atmosphere and against the oxygen-feeding outer tube, that the distance between the lance and the edge of the operating platform is small, and that the replacement of the component parts of the lance can be effected in a simple and time-saving manner and at low cost.

The objects of the invention are attained with a blowing lance comprising two concentric tubes in such manner that the head of the blowing lance is designed as a gastight housing in which an insert member made of wearresisting material is replaceably inserted, said insert member having a curved bore which connects the supply con- 3,291,471 Patented Dec. 13, 1966 ice duit for the suspension with the central inner tube. Advantageously the insert member has a cylindrical shape and is pressed against the bottom of the housing by a spring element which is arranged between the insert member and the removable cover of the housing.

According to a preferred embodiment of the invention the connection of the bore in the insert member with the central inner tube may be effected by means of a seat portion of conical shape, which is fitted into the bottom of the housing. In this case the diameter of the bore through the seat portion is reduced to the diameter of the inner tube.

In the drawing which shows a vertical longitudinal sectional view, the invention is explained more fully by way of an exemplary embodiment.

The water-cooled blowing lance 1, which is adapted to be lifted and lowered, consists in its upper part, which is of particular concern for the invention, of the outer tube 2 and the inner tube 3. The outer tube 2 is connected to the oxygen conduit 4. The head of the blowing lance is formed by a gas-tight housing 5 consisting of the bottom 6, the shell 7 and the cover 8, the supply conduit 9 for the suspension being laterally welded into the shell 7. The cover 8 of the housing is removably secured by means of screws to the shell 7 of the housing.

According to the invention an insert member 10 of cylindrical shape is inserted into the housing, which insert member has a curved bore 11 and connects the supply conduit 9 through the seat portion 12 fitted into the bottom 6 of the housing with the inner tube 3. The seat portion 12 has a conical shape. There, the inside diameter of the bore 11 is reduced to the inside diameter of the inner tube 3. Numeral 13 designates packings which render the housing gas-tight. Numeral 14 denotes a spring element which is inserted between the cover 8 and the insert member 10 whereby the insert member 10 is pressed against the bottom of the housing.

The insert member is made of non-abrasive material. The curved bore has the task to deflect the suspension into the inner tube 3 Within a minimum of space. Thus, the distance between the lance and the operating platform is kept small.

The construction according to the invention has, above all, the advantage that the insert member does not require particular accuracy of working. As the sealing is effected by the gas-and pressure-tight housing, any inaccuracies of working will only cause the existing gaps to be filled entirely with lime dust which does not cause any adverse effects on the lime dust supply. Replacement of the insert member is easily feasible by detaching the cover of the housing, without having to lift heavy parts. The housing and the insert member may be provided with a guide which prevents the insert member from being turned during operation or from being inserted in a wrong angular position.

What I claim is:

1. A blowing lance for carrying out top-blowing processes, comprising two concentrically arranged tubes, the outer of said tubes being connected to a blowing gas supply conduit and the central inner tube being connected to a supply conduit carrying a suspension of finely divided solid substances in a blowing-gas, the head of the blowing lance being designated to form a gas-tight housing in which an insert member made of wear-resisting material is replaceably inserted, said insert member having a curved bore which connects said suspension supply conduit with said central inner tube.

2. A blowing lance for carrying out top-blowing processes, comprising two concentrically arranged tubes, the outer of said tubes being connected to a blowing gas supply conduit and the central inner tube being connected to a supply conduit carrying a suspension of finely divided solid substances in a blowing gas, the head of the blowing lance forming a gas-tight housing comprising a substantially cylindical shell having an inlet connected to said suspension supply conduit, a bottom part having an outlet connected to said central inner tube, and a removable cover, an insert member made of wear-resisting material and having a curved bore therein being replaceably arranged in said housing in such manner that one end of said bore is aligned with said inlet and the other end of said bore is aligned with said outlet.

3. A blowing lance as set forth in claim 2, wherein a spring element is arranged between the removable cover and the insert member so as to press said insert member against the bottom part of the housing.

4. A blowing lance as set forth in claim 2, wherein a seat portion of conical shape is fitted into the bottom of the housing, said seat portion having a tapered bore so as to reduce the inside diameter of the bore of the insert member to the inside diameter of the inner tube.

5. A blowing lance as set forth in claim 2, wherein the insert member is secured to the housing shell to prevent the insert member from turning and to avoid displacement of the bore therein out of alignment with the inlet and the outlet.

References Cited by the Examiner UNITED STATES PATENTS 1,153,684 9/1915 Grifiin 30264 X 2,508,874 5/1960 Turnbull 239591 X 3,166,621 1/1965 Carlson 266-41 X CHARLIE T. MOON, Primary Examiner.

J. M. ROMANCHIK, JR., Assistant Examiner. 

1. A BLOWING LANCE FOR CARRYING OUT TOP-BLOWING PROCESSES, COMPRISING TWO CONCENTRICALLY ARRANGED TUBES, THE OUTER OF SAID TUBES BEING CONNECTED TO A BLOWING GAS SUPPLY CONDUIT CARRYING A SUSPENSION OF FINELY DIVIDED SOLID SUBSTANCES IN A BLOWING-GAS, THE HEAD OF THE BLOWING LANCE BEING DESIGNATED TO FORM A GAS-TIGHT HOUSING IN WHICH AN INSERT MEMBER MADE OF WEAR-RESISTING MATERIAL IS REPLACEABLY INSERTED, SAID INSERT MEMBER HAVING A CURVED 